Power amplifiers (PA) in radio frequency (RF) circuits are typically implemented in heterojunction bipolar transistors (HBTs). Normally, there is a tradeoff between PAs having high power and PAs having high speed. For example, increasing the power of an HBT typically coincides with decreasing the operational speed of the same HBT and vice versa.
But in applications such as in 5G systems, the devices are expected to operate at very high speeds, e.g., up to 100 GHz. Also, a certain amount of output power should be maintained for stable operation. Therefore, it would be desirable to implement power amplifiers that operate at both high power and high speed.